Impurities in the air, including tobacco smoke, bacteria, formaldehyde and radon, all have a deleterious effect on the comfort and health of persons breathing such air, particularly in an indoor environment. Previous efforts to remove smoke and impurities from the air have included the provision of filter systems and electrostatic precipitators. Filter systems include fans that are generally rather noisy and, particularly as tars and other impurities accumulate on the blades, tend to vibrate and intensify the noise factor. In addition, since the filters used in such systems have to allow for free passage of air, they do not block out and remove more than a small fraction of the sub-micron particles carried in the air, and such minute particles constitute the more damaging components of the air being inhaled. Moreover, to the extent that such filters do effect the collection of cigarette tars and other particles, they tend to become malodorous, and require periodic cleaning and/or replacement.
Similarly, electrostatic precipitators require substantial power for both the fan and the ionizing electrodes and the collector plates require periodic cleaning.
The present inventors previously developed an ashtray wherein the cigarette or cigar is made to act as one of the ionizing electrodes so that the smoke is ionized as it is produced and deposits on a collector, which is oppositely charged. The ashtray includes, as a separate optional feature, an air ionizing electrode which simply emits free air ions to the surrounding atmosphere, whereby ambient smoke and other impurities in the atmosphere are charged to precipitate on the collector or any other nearby surface at ground potential. There is no provision for "aiming" such electrode or adjusting the distance between electrode and collector.